Courage needed on icy roads? (4)

I believe the answer is:

grit

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'courage' is the definition.
(I've seen this before)

I don't understand the remainder of the clue.

(Other definitions for grit that I've seen before include "Hard particles for firmness of character" , "Gumption or small pieces of stone" , "called for on icy roads" , "Determination - small stones" , "Pluck; sand particles" .)

I've seen this clue in the Evening Standard and The Globe and Mail.

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